strict pathogens and some observers have looked at them as possessing a digestive power. In the digestive tract of the animals eating large quantities of carbohydrate as cellulose, nature provides for its use by rumination and by supplying a large hind-gut, by which means secondary mastication and bacterial decomposition of the cellulose capsule insures its full use. Possibly a similar usefulness may be finally ascribed to some animal microbes or even larger metozoa. The rôle of vegetable parasites in the causation of disease among wild animals seems as undoubted as it is in the human being and the pathologic results are usually as clear, at least for the entities of which we have exact data, based upon comparisons with man and domestic animals. There seems to be no essential difference among mammals between the pathological pictures of infectious septicemias, the mucous and serous membrane inflammations and tuberculosis for example. They are characterized by fibrinous, purulent or infiltrative inflammations which may go on to necrosis or repair, by fever, by leucocytosis and by evidences of resistance—all of these things occurring in a similar way throughout the class. Of course not all animals are receptive to all infections since specific racial and generic immunities exist, but the basic response in terms of pathology is similar. There are no normal means of judging the susceptibility of wild animals on their native heath to the important pathogens of civilization, pneumococci, streptococci, staphylococci, cholera bacilli, the typhocolon group, the Friedlander group and others, but it is interesting to note that in captive conditions they evince some receptivity to these germs or their congeners. The pneumococcus takes a fairly heavy toll in zoological collections every year and the Friedlander bacillus, not a very common cause of human pneumonitis, has been seen here and at London.